2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/229490We argued in a previous paper [R. A. Vanderveld et al. 2006, arXiv:astro-ph/0602476] that negative deceleration parameters at the center of symmetry in Lemaitre-Tolman-Bondi cosmological models can only occur if the model is not smooth at the origin. Here we demonstrate explicitly the connection between non-smoothness and the failure of positivity theorems for deceleration. We also address some confusion that has arisen in the literature and respond to some recent criticisms of our arguments.4 pages, no figures, revtex4Cosmology and Nongalactic AstrophysicsGeneral Relativity and Quantum Cosmologytext